Crimping is a cold-working process used to join mutually-deformable objects, at least one of which is typically constructed of metal or another malleable material. For example, in forming a crimped electrical connection, a wire may be deformed with respect to a barrel or a ferrule in order to form a crimped joint, hereinafter referred to as a crimp for simplicity. Crimping tools are used to mechanically join a ferrule to a wire. An improperly crimped ferrule/wire connection may contain loose wires, and the deformation of the ferrule may provide an inadequate clamping force.
Conventional quality testing of a pull-out force of a crimp is performed manually. That is, the crimp, along with any settings of the particular tool used to form the crimp, are evaluated via the pull force required to separate the crimped ferrule from the wire or bundled wires therein. Once the crimps are determined to support a threshold minimum load, usually set on the basis of wire gauge and crimp ferrule qualities, the crimping tool is placed in service. However, conventional pull testing may inadequately measure transport across the crimps, and therefore such pull test results are not closely linked with electrical conduction properties of the resultant crimp.
Measures of the quality of the electrical conduction across a crimp may be derived from the ability to transmit ultrasonic energy across the ferrule—wire interface, since electrical and ultrasonic transmission are both fundamentally related to the asperity density at the wire-ferrule interface. One method of ultrasonically analyzing a crimp is described in U.S. Pat. No. 7,181,942 to Yost et al., the contents of which are hereby incorporated by reference in their entirety.